You seem to have an extra level, a hash with a single key.

$ref->{Honda}->[0]="Civic";
$ref->{Honda}->[1]="Accord";
$ref->{Toyota}->[0]="Camry";
$ref->{Toyota}->[1]="Tundra";
$ref->{Toyota}->[2]="Corolla";
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By the way, the arrow between indexes can be omitted.

$ref->{Honda}[0]="Civic";
$ref->{Honda}[1]="Accord";
$ref->{Toyota}[0]="Camry";
$ref->{Toyota}[1]="Tundra";
$ref->{Toyota}[2]="Corolla";
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It seems odd to refer to array indexes using a constant.

$ref->{Honda}  = [ qw( Civic Accord         ) ];
$ref->{Toyota} = [ qw( Camry Tundra Corolla ) ];
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Or if you were in a loop,

push @{$ref->{Honda}}, 'Civic';
push @{$ref->{Honda}}, 'Accord';
push @{$ref->{Toyota}}, 'Camry';
push @{$ref->{Toyota}}, 'Tundra';
push @{$ref->{Toyota}}, 'Corolla';
[download]